


One Planet Isn't Enough

by Geonn



Category: Doctor Who (2005), Sanctuary (TV)
Genre: Action/Adventure, Alien Flora & Fauna, Alternate Universe - Future, Crossover, F/F, Fire, Romance, Swords & Fencing, Women Being Awesome, Zero-gravity sex
Language: English
Status: Completed
Published: 2012-05-06
Updated: 2012-05-06
Packaged: 2017-11-04 23:12:21
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,163
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/399252
Author URL: https://archiveofourown.org/users/Geonn/pseuds/Geonn
Summary: <blockquote class="userstuff">
              <p>After five hundred years on Earth, Helen Magnus sets her sights higher.</p>
            </blockquote>





	One Planet Isn't Enough

**Author's Note:**

  * For [MatildaSwan](https://archiveofourown.org/users/MatildaSwan/gifts).



Helen twisted her right hand upside down and pressed her palm against the tooled leather of the grip. She flexed her fingers and curled them, her muscles tensing as she pulled. She had one boot braced against the stone, her elbow pointed toward the stone cathedral ceiling of the cave. She grimaced as she pulled, straining muscles in her back as she tilted her body to remove the gleaming metal from the hole in the rock that was barely big enough to accommodate it.

"Faster, darling!"

Helen grunted and cursed under her breath. The voice was mostly echo, its origin farther down the winding corridor Helen had just hauled ass through. She added her other hand, lowering her center of gravity to use her weight to force the weapon out of its home. Finally, it moved. Just an inch but enough to shift the balance. It slid free easily, and Helen removed the sword from the stone. She grinned as she held the blade in front of her face. She could see her reflection in the burnished steel.

"Durendal embedded in the cliff face... brilliant."

"Helen...!"

Reminded of the moment's urgency, Helen turned and ran back the way she had come. Leaving Earth had been one of the hardest decisions Helen had ever made. Leaving behind the work of half a millennium took time, and planning, and thirty years after the invitation was extended, Helen was ready. She spent the three decades preparing to step aside, handing over greater responsibilities to those she trusted until she was free to cut ties completely. When she was ready, River Song returned. They reunited on the Dead Bridge, and River crossed her arms over her chest. "I've been waiting almost twenty minutes... are you ready yet?" 

Helen carried Durendal through the cavern, still hearing the sound of battle up ahead. Now that she'd spent a few decades traveling with River, she knew that leaving Earth hadn't been brave. No braver than a high school graduate moving on to college. She had kept her focus on a single, relatively-insignificant planet when there was an entire universe that required her unique perspective. 

And she couldn't have hoped for a better companion. River truly was her equal, if not her superior, in every sense of the word. And Helen knew the feeling was mutual. River was completely capable of stepping back to let Helen take the lead if a situation required it. After five centuries of protégés and lovers, it was a revelation to work with someone who didn't require any handholding whatsoever. It was freeing, and it gave Helen the chance to hand over the decisions to someone else now and then. And the sex...

Oh. The sex...

Helen entered the cavern with the sword brandished, resting on her shoulder as she assessed the situation. In her absence, River's position had been overrun by the pwe. That was as close as she could guess their name at any rate. River pronounced it by pursing her lips and flicking her tongue against the opening as she exhaled a single syllable. They were ant-like crabs with long, bisected forelegs that ended in nine-legged spider-like fingers. They balanced on their back half and aggressively waved their spindly spider hands like boxers spoiling for a bout.

River was holding them off with a makeshift flamethrower. She glanced over, having caught the movement of Helen's arrival in her periphery, smiled. "Took you long enough."

"Did you miss me, darling?" Helen leapt onto the same level as River, who twisted at the waist and pressed her shoulders to Helen's. "You certainly seemed to have matters well in hand."

"Flatterer." She flicked the flamethrower on again and the creatures shrieked and backed away. The flame's light caught the edge of the blade as Helen swung it at the creatures. Their multifaceted eyes reflected the weapon and they recoiled from the sight of it. River watched as they backed off. "Not so mindless after all..."

"Told you so."

River swept a tongue of flame across the stone and the pwe scurried up the near-vertical cliff to escape. "You can punish me for my disbelief later."

Helen smiled. "Spanking? Shall I tie you to the bedposts again?"

"To the victor," River said.

Helen knew she wasn't just teasing. After their relationship became physical on a brief layover on an unnamed moon ( _"I've lived far too long to be coy, Dr. Song. If you would like to join me in my bed, I would be delighted to make room."_ ), they had never shied away from the physical side of their relationship. They both took lovers, male and female, during "excitement," but when they were simply traveling from one planet to the other, they shared a bed to combat loneliness they both knew all too well. 

"The pthwuh--"

"Pwe," River corrected.

"Pfa."

"P...w...e..."

"These creatures have a strong mythology. Had you taken the time to examine the glyphs written on the walls, you would have known they fear this weapon. Not only that, it warns them away from inadvertently stumbling over it on their--" She swung and split off one of the creature's forelegs. It shrieked and the others carried their wounded brethren away. "--travels. Unfortunately it has the added effect of leading their enemies directly to the one item that can hold them off." She looked over her shoulder at River. "But no. The brilliant Dr. Song simply must blunder forward without care or concern..."

"Yes, yes, shall we move on before these pwe find their courage?"

"After you," Helen insisted. 

River moved for the exit, and Helen covered her retreat with the sword. Once they reached the cave entrance, the pwe seemed to realize their prey were close to escape and redoubled their attack. Helen had to cease threatening and turned to actual defense. She stabbed, sliced, and bashed the creatures as she ran backwards, the chitinous bodies clacking against the stone as the flood of pwe followed her into the narrow cavern where their ship was waiting. Occasionally a creature became stuck on the blade and Helen was forced to use one pwe body to hit another, and the two would fall away together.

Helen heard the door of their ship slid open. One of the pwe lunged and sliced at her leg, and Helen cried out and lost her balance jumping away from it. She tumbled, landing on her right side as the creatures surged forward with their spider-hands stretched out and held eagerly open. Helen sliced at what she could, but there were too many. She was going to--

Flame filled the air above her, and Helen dropped flat to the stone floor as the pwe, so focused on their prey, became ignited. They fell back and landed on the creatures behind them, and the swarm turned into a writhing mass of fireballs. River grabbed Helen's coat collar and hauled her backward, through the open doors of the ship, and she kicked the doors shut behind her.

The interior of the ship was so silent that it pressed against Helen's ears, and River dropped to her knees. The flamethrower hit the ground with a clatter, and she spread her fingers on her thighs as she caught her breath. Helen pushed herself up on her elbows and, after a moment, nudged River's arm with her boot.

"That was close. Thank you."

River squeezed Helen's ankle. "I'd have never made it without you. So your rescue enabled me to rescue you."

Helen grinned. "Quite a symbiotic relationship we've created."

River crawled up Helen's body and straddled her legs. Their faces were inches apart when River smiled and said, "So. To the victor go the spoils. How shall I be punished?"

Helen brought her hand up and twisted one of River's curls around her index finger. She kissed both of River's cheeks and then lifted her head slightly in the way they'd adopted for speaking to the occasional third member of their troika. "Idris... three-quarters gravity."

Helen suddenly felt lighter, as if she had dropped a hundred pounds. She flattened her boots against the ground, and River was pulled against her as if they'd been magnetized. She spread her legs, settling her weight against Helen's pelvis as her knees rose off the ground. River arched an eyebrow and flicked her tongue against Helen's top lip.

"Idris," River said. "Half-grav."

The ship responded again, and this time Helen drifted up from the ground. She opened River's pants, and River lifted herself to let the flimsy material be eased down and off. She was left in a shirt that draped enough to cover her waist, and boots that ended just below her knee. She settled on top of Helen like someone mounting a horse, and Helen flattened one hand against the floor to push them higher. They floated as if through viscous liquid, Helen's lower body turning slowly with the tide of air flow. 

"Idris," Helen said. "Quarter grav. Hold there, please."

They floated five feet off the ground as they properly kissed. River managed to get Helen's pants undone, and the force of pushing them down propelled them forward. The pants ended up bundled over the top of Helen's boots, and she left them there so she could use both feet to steer. Helen unbuttoned her shirt and shrugged out of it. The material slipped off her extended hand, drifting. Helen closed her eyes as River kissed the black lace of her brassiere, teasing the nipple to full erection with firm strokes of her tongue. Helen threaded River's hair, which was floating in the lighter gravity, through her fingers.

"Your punishment, Dr. Song, is to ride me."

"Oh, always so harsh." She licked Helen's cleavage. "Disciplinarian..."

Helen purred as she arched her back. The change in her posture caused her and River to slowly flip, and Helen used her feet to kick off the central tower of their control room. She opened her eyes and saw Durendal and the flamethrower were caught in each other's orbits by the front door. "Idris," she whispered, "isolate the weaponry if you would..."

"Of course, Dr. Magnus."

River grinned and nipped Helen's stomach. "Idris, you nasty thing. I knew you watched us."

Idris' giggle faded into silence as Helen and River oriented their bodies so their heads were pointed at the ground, their feet twisting in the air. Helen slid her hands under River's collar and raked her fingernails over the smooth flesh of River's neck. River writhed as she moved lower and then sat up. One hand on Helen's chest, fingers curled around her bra strap, River pressed her center against Helen and began to writhe. Helen bumped against something and they both pushed off, River giving them a counter-clockwise spin as Helen's guided them upward. 

Their bodies twisted in mid-air. "Up" and "down" were completely foreign concepts to them as they danced through the air. River threw her head back, riding Helen through the air and reaching back to cup the crotch of Helen's panties with her free hand. Helen parted her lips in a silent gasp and gripped River's thighs with both hands. 

"Don't stop..."

"I don't intend to, love." She spread her fingers over the material of Helen's underwear, then pressed with her middle and ring fingers. Helen massaged River's thighs, arching her back as they drifted. Helen's right knee was bent and her left leg hung down and kept them steady like a boat's tiller. River pressed down against Helen, who pressed up to accommodate for the lessened gravity. They became their own gravity, orbiting each other, sweat dripping upward from River's breast until it splattered against the underside of Helen's chin. Helen's sweat spread outward from her sternum and made her chest appear rain-splattered. River's hair hung around her head like a sunburst, and Helen's hair swam like a gossamer spider web. 

They hit something - floor, ceiling, wall, Helen was beyond identification - and drifted leftways. Helen came first, and River began to ride her harder to join her in orgasm. Soon their cries died down, and River sank toward Helen. Helen put her arms around River's neck and they kissed as the air currents pushed them through the open space of their ship.

"Shall I decrease the temperature, Doctors? You both seem quite... overheated."

Helen could swear she heard a smile in the AI's voice. "Mm. Perhaps for a few minutes, Idris." Helen kissed River's temple as they spun. "You've accepted your punishment well, Dr. Song. Consider yourself absolved."

"Thank you, Dr. Magnus." She stroked Helen's thigh. "So... where shall we go next?"

Helen looked toward the window, orienting herself to the room. "Mm. We'll figure that out soon enough. It's such a big universe..."

"Very true."

Helen nuzzled River's neck. A huge universe, incomprehensible in its size, was waiting for her. It had waited this long for her help; she could spare an hour or two for cuddling with the woman she loved.


End file.
